Feeding mechanism for rock drills



June 2, 1936. J. c. CURTIS FEEDING MECHANISM FOR ROCK DRILLS Filed May 19, 1934 2 Sheets-Sheet l N ME JOHN c cu/e 775 INVENTOR ATTORNEY lune 9 J. c. CURTIS FEEDING MECHANISM FOR ROCK DRILLS 2 Sheets-Sheet 2 Filed May 19, 1 934 E v 3 Q m n IO 1% J HN C. CU/ET/S INVENTOR ATTORNEY Patented June 2, 1936 UNETED STATES PATENT OFFICE FEEDING MECHANISM FOR ROCK DRILLS Application May 19, 1934, Serial No. 726,521

5 Claims.

This invention relates broadly to rock drills, but more particularly to feeding mechanism for rock drills of the drifter type.

One object of this invention is to produce a mechanism wherein the jars or vibrations imparted to the drill during its normal operation are utilized for feeding the drill toward or away from the work.

Another object of this invention is to provide a feeding mechanism with a device capable of controlling the rate of speed of the feeding motion of the rock drill irrespective of the amplitude of the vibration or jars imparted thereto.

Another object of this invention is to provide a rock drill with a feeding mechanism having a device, permitting the drill to be manually movable on its support irrespective of its association with its feeding mechanism.

Another object of this invention is to provide a rock drill with a feeding mechanism operated by the jars imparted to the drill during its normal operation, and having means for locking the drill against relative longitudinal movement with respect to its support irrespective of the jars imparted to the drill.

Other objects and advantages more or less ancillary to the foregoing reside in the specific construction and aggroupment of the elements peculiar to this structure, as will become apparent from a more complete examination of this specification.

In the drawings which illustrate the invention:

Fig. 1 is a longitudinal View partly in section of a rock drill embodying the invention.

Fig. 2 is an enlarged cross sectional view taken in a plane indicated by line 22 in Fig. 4.

Fig. 3 is an enlarged longitudinal sectional view taken in .a plane indicated by line 3-3 in Fig. 2.

Fig. 4 is an enlarged cross sectional view taken in a plane indicated by line 44 in Fig. l, illustrating the throttle valve in one position.

Fig. 5 is a View similar to Fig. 4 illustrating the throttle valve in another position.

Figs. 6 and 7 are views illustrating a portion of Fig. 4 with the throttle valve in different positions.

Referring to the drawings in which like symbols designate corresponding parts throughout the several views, l9 represents the cylinder of a fluid actuated drilling motor having reciprocable therein a piston capable of delivering its blows to a cutting tool slidably mounted within a front housing l2. The lower portion of the cylinder I0 is formed with a duality of longitudinally extending guides l3. Secured to the cylinder l0, there is a back head l4 within which is rotatably mounted a throttle valve operable by means of a throttle valve handle l5. The drilling motor is one of the common drifter type, and since the motor itself does not constitute a part of the present invention, no further explanation is though necessary other than directing the attention to the apertured lug l6 depending from the cylinder ID. The left side wall of the lug I6 is formed with a shoulder or stop Usually this apertured lug is adapted to receive a feed screw nut cooperating with a manually rotated feed screw for feeding the machine toward or away from the work.

The cylinders guides l3 are slidably mounted within longitudinally extending ways I8 formed within the upper portion of a stationary support or shell I9 having secured to the lower wall thereof a cone by which the shell may be affixed to any suitable support such as .a tripod.

Referring now more particularly to the present invention, 2| represents a gear rack secured in the interior of the shell IS in parallelism with the guide ways l8 by a plurality of screws 22. Located immediately after the back head l4, there is a housing 23 formed with a lateral stem 24 extending through the cylinder apertured lug l6. At its base, the stem 24 is provided with a fiat surface 25 capable of engagement with the stop ll for locking the housing 23 against rotation. The outer end of the stem 24 is threaded to receive a nut 26 by which the housing 23 is secured to the cylinder Ill. The upper portion of the housing 23 located above the shell I9 is provided with an enlarged counterbore or rotor chamber 2'! having secured therein, in screw threaded engagement with the outer end portion thereof, a plug 28 formed with a flange 29 capable of fluid tight engagement with the end wall of the housing 23. Leading from the bottom of the counter bore or rotor chamber 21 in eccentric relation with the axis thereof, there is a bore 30 formed toward its outer end with an annular shoulder 3|. Opposite the rack 2|, the housing is provided with a laterally disposed circular opening 32. Rotatable within the rotor chamber 21, there is a rotor 33 formed with shaft 34 rotatably mounted within the bore 30. Toward its outer end, the shaft 34 is reduced for engagement within a bushing 35 secured within the bore 3|] against longitudinal movement therein by its engagement with the shoulder 3|. Disposed within the circular opening 32, and engaging the teeth of the rack 2|, there is a gear 36 secured to the shaft 34 by means of a key 31. The rotor 33 is provided with a plurality of equally spaced vertical slots 38. Within each of the slots is slidably mounted a blade 39, formed with a restricted bore 40 adapted to receive a compression spring 4| for constantly urging the blade toward the inner wall of the chamber 21. The bottom portion 01. each of the slots is connected to the circumferential wall of the rotor 33 through a restricted port 42.

Rotatably mounted within the housing 23, there is a feed controlling throttle valve 43 secured therein by a plug 44 in screw threaded relation with the housing 23. The throttle valve 43 is formed with a stem 45 extending through the plug 44, and having secured at the outer end thereof a handle 46. The interior of the throttle valve 43 is conveniently machined to form an open end chamber 41 having a port 48 leading from the bottom thereof to the periphery of the throttle valve through two radially disposed ports 49 and 50, while the chamber 41 is also connected with the periphery of the throttle valve through a radially disposed port 5|. The bottom of the chamber 41 is formed with an annular protuberance constituting a valve seat 52. Slidably mounted within the chamber 41, there is a disc or plate valve 53 constantly urged against the valve seat 52 for fluid tight engagement therewith by the efiort of a compression spring 54. Outside of the marginal edge of the valve seat 52, the plate valve is provided with aplurality of relatively small ports 55. Leading from one side of the rotor chamber 21, there is a port 56 in constant communication with the throttle valve 43 through ports 51 and 58, while the opposed side of the rotor chamber 21 is capable of communication with the throttle valve 43 through the ports 59 and 60. The rotor is of the common type wherein pressure exerted on one side of the blades will cause'the rotation of the rotor. To prevent the undesirable action of back pressure usually encountered in motor of this type, there are provided relatively narrow grooves 6| and 62, the former in constant communication with the port 56 while the latter is in constant communication with the port 59. Both of these grooves fall short of the line engagement between the rotor and the internal wall of the chamber 21. Each of the blades 39 are provided with a transversally disposedport 63 the purpose of which will be explained later. Leading from the passage58 to the exterior of the housing, there is a screw threaded bore 64 adapted to receive, in screw tight engagement therewith, a filler plug 65. It is to be understood that this plug can be located in any convenient position and need not open into the passage 59, but may open into any of the passages formed within the housing. The entire system of passages together with the space provided between the rotor 33 and the inner wall of the rotor chamber 21 is filled with a non-compressible fluid such as oil. The filling of the system can take place through the bore 64 after the plug 65 has been removed. The system is entirely air tight, packings such as 66, 61, 68, and 69 being provided to prevent any possible escape of the fluid from the housing.

The operation of the device is as follows: When pressure fluid is admitted into the cylinder ill] to cause the reciprocation of the hammer therein, the jars resulting from the reversal of the stroke of the hammer are transmitted to the rock drill,

thus tending to cause a reciprocatory or longitudinal vibratory motion of the rock drill relative to the shell I9. Due to the engagement of the rotatable gear 36- with the stationary rack 2|,

the reciprocatory movement of the drill will normally cause the oscillation of the gear 36 and the consequential oscillation of the rotor 33, since the latter is integrally connected to the gear by the key 31 and shaft 34. Assuming the feed control throttle valve 43 to be positioned as illustrated in Fig. 5, the movement of the rock drill toward the work will cause, through the engagement of the gear 35 with the stationary rack 2|, the rotation of the rotor 33 in a clockwise direction. During this rotation of the rotor, the fluid within the rotor chamber 21 displaced by the blades 39, is forced out of the chamber 21 through the port 56 into the throttle port 48 through the ports 58 and 49. The pressure exerted on the fluid by the movement of the blades in a clockwise direction will cause the plate valve 53 to separate from its seat 52, thus permitting the flow of the fluid into the throttle valve chamber 41 via the restricted ports 55 formed in the, plate valve 53. From the throttle valve chamber 41, the fluid is readmitted into the rotor chamber 21, through the passage 60 and 59.

The alternative movement of the rock drill away from the work will similarly tend to cause the rotation of the rotor in a counterclockwise direction. In this instance, however, the fluid within the motor chamber 21 which would have to be displaced by the blades 39 to permit the rotation of the rotor in a counterclockwise direction, is prevented to escape from the chamber 21 through the passage 59, the latter being closed by the throttle valve 43. The pressure exerted on the fluid by the blades 39 tending to rotate in a counterclockwise direction, is transmitted to the fluid in the throttle valve chamber 41 through the passage 68, thus acting, together with the compression spring 54, on the plate valve 53 to maintain the latter against the valve seat 52. Since the fluid is prevented to escape from the rotor chamber 21 through the passage 59, it will be understood that the rotation of the rotor 33 and that of the gear 36 in a counterclockwise direction, is impossible, thus preventing the movement of the rock drill away from the work. In this manner, the jars or longitudinal vibrations imparted to the rock drill will cause the positive movement of the rock drill in one direction, and prevent its movement in the other direction.

When it is desired to feed the rock drill rearwardly or away from the work, the feed control throttle valve may be positioned as illustrated in Fig. 4. In this instance, the counterclockwise rotation imparted to the rotor 33 by the rearward movement of the drill, will cause the blades 39 to displace the fluid in the rotor chamber 21 via the port 59, throttle valve passage 49 and 48. The pressure exerted on the fluid will cause the movement of the plate valve 53 away from its seat 52, thus permitting the flow of the fluid through the plate valvei passages 55 into the throttle valve chamber 41, from where it will be readmitted into the rotor chamber, via the throttle valve port 5|,

and ports 51 and 56. The alternative movement of the rock drill toward the work will similarly tend to cause the rotation of the rotor in a clockwise direction. The fluid in the rotor chamber 21 which would have to be displaced by the blades 39 to permit the clockwise rotation of the rotor, is prevented to escape therefrom through the port 56 and 58, the latter being closed by the throttle valve 43. The fluid under pressure admitted from the port 56 into the throttle valve chamber 41 through the ports 51 and 5|, will simply cooperate with the efiort of the compression spring 54,

to maintain the plate valve 53 against its seat.

Since the fluid is prevented to escape from the rotor chamber 21, it will be understood that the rotation of the rotor in a clockwise direction is impossible, thus preventing the corresponding rotation of the gear 35, and consequently preventing the forward movement of the rock drill.

During the rotation of the rotor in a clockwise direction, the fluid within the chamber 21 located between the opening of the port 55 therein and the line engagement of the rotor with the internal Wall of the chamber 2?, is free to be displaced therefrom through the relatively narrow groove 5!, preventing thereby a back pressure which would tend to prevent the rotation of the rotor. Simultaneously the suction which would normally take place in the rotor chamber between the line contact of the rotor with the inner wall of the chamber 2'! and the opening of the port 59, will be released through the groove 62.

During the ,rotation of the rotor 33 and the consequential rotation of the blades 39, the volume of one of the large compartments between two of the blades will gradually diminish while the volume of the next compartment will increase proportionally. If the fluid within the diminishing compartment, was not permitted to escape therefrom, it would prevent the rotation of the rotor. In the present construction, this undesirable feature is prevented by the restricted ports 63 provided through the blades 39. These ports are located with respect to the ends of the blades in a manner permitting the ports to move in and out of the rotor. Immediately before the volume of one of the large compartments diminishes, the port 63, of the blade dividing the two larger compartments, will be out of the rotor 33, thus permitting the flow of the fluid from one of the compartments to the other, and thereby permitting the rotation of the rotor. Any fluid which might escape from the rotor chamber 21 to the bottom of the slots 38 through the necessary clearance existing between the blades and the side walls of the slots, will be forced out of the slots during the inward movement of the blades therein through the restricted ports 42, which are capable of communication with the narrow grooves 6i and 62.

The rate of speed of the feeding motion imparted to the drill toward or away from the work may be regulated by the feed control throttle valve 43. This valve may be positioned to permit a more or less complete registration of its port 49 with either the port 58 or 59, thus varying the velocity of the fluid through the system of passages, and thereby regulating the speed of rotation of the rotor together with the rate of speed of the feeding motion imparted to the rock drill.

When it is desired to manually slide the rock drill on its support toward or away from the work, the feed control throttle valve 53 may be positioned as illustrated in Fig. 6. In this instance, the port 56 is directly connected with the port 59 through the port 58, and throttle valve port 50, thus permitting the free flow of the non-compressible fluid within the system irrespective of the sense of rotation of the rotor 33, and thereby permitting a free forward or backward longitudinal movement of the rock drill on its support.

When it is desired to lock the rock drill against its longitudinal movement relative to the shell IS the feed control throttle valve may be positioned as illustrated in Fig. 7. In this instance, the various passages affording communication of the passage 56 with the passage 59, are closed by the feed control throttle valve 43, thus preventing the escape of the fluid from the rotor chamber 21 and thereby preventing the rotation of the rotor 33 and gear 35. The gear 35 being held against rotation will prevent, due to its engagement with the rack 2|, the longitudinal movement of the rock drill.

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or confining and it is to be further understood that various rearrangements of parts and modification of structural detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

I claim:

1. In a feeding device, the combination with a support and a motor slidable thereon, a piston reciprocable within said motor imparting jars thereto to move the motor relatively to the support, a housing having a member therein associated with said motor and normally movable thereby in two directions due to the jars imparted to said motor, non-compressible fluid within said housing normally displaced therein due to the movement of said member, and means for controlling the direction of movement of said member and consequently the direction of movement of said motor, said means including a single throttle valve operable for selectively controlling the direction of travel of the non-compressible fluid within said housing, and a single check valve for preventing the non-compressible fluid to travel within said housing in a direction adversed to that resulting from a predetermined position of said throttle valve.

2. In a feeding device, the combination with a support and a motor slidable thereon, a piston reciprocable within said motor imparting jars thereto to move the motor relatively to the support, a housing having a member therein associated with said motor and normally movable thereby due to the jars imparted to said motor,

non-compressible fluid within said housing normally displaced therein due to the movement of said member, a throttle valve within said housing having a check valve operatively mounted therein, a plurality of passages, two of said passages leading from said member to said throttle valve, r

said check valve being automatically operated for controlling the displacement of the fluid within said passages in a manner permitting the movement of said motor in one direction and preventing the movement thereof in the other direction,

said throttle valve being manually operated for selectively controlling the direction of movement of said motor.

3. In a feeding device, the combination with a support and a motor slidable thereon, a piston reciprocable within said motor imparting jars thereto to move the motor relatively to the support, a housing having a member therein associated with said motor and normally movable thereby due to the jars imparted to said motor, a plurality of passages within said housing in constant communication with said member, noncompressible fluid within said passage normally displaced therein due to the movement of said member, a single check valve automatically operated for controlling the displacement of the fluid within said passage in a manner permitting the movement of said motor in one direction and preventing the movement thereof in the other direction, and a single throttle valve manually operated means for selectively controlling the direction of movement of said motor.

4. In a feeding device, the combination with a support and a motor slidable thereon, a piston reciprocable Within said motor imparting jars thereto relatively to the support, of a mechanism having a predetermined amount of fluid stored therein, unitary means within said mechanism associated with said motor and subjected to the action of said fluid for preventing the movement of said motor in one direction, and unitary means associated with said mechanism operable for selectively controlling the direction of movement of said motor.

5. In a transmission mechanism, the combination with a vibrating element, of a housing having a predetermined amount of non-compress ible fluid stored therein, a member within said housing associated with said element and movable thereby due to the vibratory motion of the latter, the movement of said member causing the circulation of the fluid Within said housing, and means for controlling said circulation in a manner whereby the vibratory motion of said element causes the movement of said member in one direction, and single means operable for selectively controlling the direction of movement of said member.

JOHN C. CURTIS. 

